Sound-reproducing instrument



Nov. 8, 1927. 1 648326 A. w. HARRIS SOUND REPRODUCING INSTRUMENT FiledJune 23, 19.26 2 SheeES- Sheet, l

Nova 8, 1921. 1,648,226

A. W. HARRIS SQUND REPRODUCING INSTRUMENT Filed June 23, 1926 2Sheets-Sheet 2 Patented Nov. 8, 1927.

- UNITED STATES PATENT oFF cs.

ARTHUR WILLIAM HARRIS, OF NEW YORK, N. Y., ASSIGNOR TO THE AMPLION'POM'IION OI AMERICA, OF NEW YORK, N. Y., A COBPORATION OF DELAWARE.

SOUND-REPBODUCIN G INSTRUMENT.

Application filed June 23, 1926. Serial No. 118,094.

novel construction of a sound reproducing instrument such as is nowgenerally known as a speaker or a loud speaker.

In the development of the loud speakers adapted particularly for -usewith wireless receiving sets, great difliculties have been met inunsuccessful attempts to construct a single instrument which willreproduce the low notes as well as the high notes. Experience has shownthat a speaker-which satisfactorily reproduces the low frequency notesdoes not satisfactorily reproduce the high frequency notes and viceversa.

The present invention has to do with an improved loud speaker instrumentwhich will satisfactorily and with exceeding efficiency reproduce lowfrequency notes as well as high fr uency notes. ThlS improved speakeralso as in its favor a considerably wider range of eflicient andsatisfactory re-' production than has heretofore been accomfore, toprovide a novel construction of soundplished in loud speakers of thistype.

The main object ofthis invention is,therewave reproducin mechanismwhereby notes of both low an high frequencies will be satisfactorily andclearly reproduced.

Another object of this invention is to provide a novel speaker which hasa particu larly wide range of note re roduction and which reproducesnotes of high frequencies substantially as well as notes of lowfrequencies and vice versa. I

A further and detailed object of this invention is to provide a novelcombination 40 of a relatiyely small vibrating diaphragm with a cone ofmodified form, in a loud speaker of the cone type whereby a veryadvantageous improvement with increased range of sound reproduction isobtained.

Another object ofthe invention is to supplement -a combined diaphragmand cone speaker with a born to thereby add to the total efficiency ofthe improved speaker.

A still further object of the invention is to provide a novel type ofloud speaker which is exceptionally simple in its construcf'tion andoperation and has vibrating elemanta of desirably light weight,rendering it moresensitive and permitting its manu facture at arelatively low cost.

Other objects and-advantages of the invention will be appreciated as thedetailed description below is read.

The preferred embodiment of this invention is illustrated in theaccompanying drawings wherein:

Fig. 1. is'a'n elevational view, partly in section, .0f the improvedspeaker showing a modified form of cone vibrating member af fixed to adiaphragm;

Fig. '2 is an illustration similar to Fig. 1 and includes a showing of aguard for the protection of the cone;

Fig. 3 is also an elevational view based on the "construction shown inFig. 1 and illustrates in addition thereto, the use of a horn .whichassists in the amplification of the sound waves and also cone;

Fig. 4 is a top plan view of a means for vibrating the diaphragm andcone member; Fig. 5 is a sectional view of Fig. 4 taken on the line 5-5thereof;

Fig. 6 is a sectional view of the operating mechanism shown in Fig. 4taken on the line .acts to protect the 66 of Fig. 5'; and

Fig. 7 is a erspective view of an element employed in t e mechanismshown in Fig. 4.

In producing this novel type'of simple loud speaker, there is preferablycombined two vibrating elements 1n such a satisfactory manner as toobtain a very efiicient reproduction of sound waves over anexceptionally wide range. In carrying out the'most preferred method ofcombining these elements, there is provided a vibrating art which isparticularly adapted to the e cient repro duction of notes of highfrequencies, and there is also provided a, second vibrating part whichmost efliciently reproduces notes oflow frequencies. These parts havebeen brought into association with one another so that, in their normaloperation, they vibrate in unison and efl'ect-a very pleasingreproduction of speech and musical notes over a wide range.

' In combining these two vibrating parts or elements, there resultsasound reproducing mechanism which may appropriatel be termed a compoundvibrator. It will be understood that the two elements maybe combined inanydesired manner to accomplish the desired improved result as hereinrequired to be obtained. It is believed, however that one of the reasonsfor obtainin the highly satisfactory results accomplishe according tothis invention, resides'in the fact that one of these vibrating elementsis attached to the other vibratin element at some place or portionthereo which normally vibrates during the operation of the speaker.Whether or not this is the explanation or main reason for obtaining suchadvantageous results, the improved speaker mechanism accordin to theinvention herein illustrated and produce most satisfactory results in'operation.

In describing the preferred embodiment of the invention in a particularapparatus, or instrument, reference is made especially to Fig. 1 whereina suitable base-holder 1 is illustrated as having one .of the vibratingelements in the form of a diaphr 2 mounted therein. This disk diaphragm2 is preferably of metallic construction and is fixedly or semi-fixedlymounted in the baseholder. It is preferred that thisdiaphragm 2 shall beannular and shall be either permanently and firmly mounted between a hp3 of the base-holder 1 and a cover edge 4, or between suitable rubber orresilient. sprlng gaskets. Thus, the diaphragm 2 is fixedly mounted inthe base-holder in a predeter mined manner. It is also to be undertsoodthat-this diaphra may be aflixed or permanently mounte to thebase-holder 1 in any other suitable manner.

To the diaphragm 2 there is added a second vibrating element ordiaphragm-5, preferably in the form of a cone, and it is preferred tohave this cone of materially greater size than that of diaphragm 2. Thiscone 5 in addition'to constituting a vibrating member, also may functionas a horn for amplifying the sound waves 'whichare set up within theconfines of the element 5 by the vibrations of that part or portion ofthe diaphragm 2 confined within. or lying adjacent. to' the smaller edgeof the cone.-

The conevibrating element or part'may be made of any suitable materialwhich is adapted to reproduce sound waves when this material isvibrated. In this instance, it is advantageous to make the cone'5 of a,suitable paper construction which may be impre nated or not as desired.The thickness of t e paper'or the amount of impregnation of the paperselected for the purpose of giving a required stifl'ness may of coursebe varied in order to obtain the desired sound wave reproduction.

The cone 5 may be held in association with the diaphragm 2 in anydesired manner in order to obtain the most efiicient results. It

. has been found that the cone may be suitably smallest'diameter of thecone and eseribed has proven to;

and fir-mly held in association with the diaphragm 2 by forming 'aflange 6 at the asting or otherwise causing the flangeto ad ere to thediaphragm 2.

In considering the compound vibrator as a single or unitary element thecone part thereof may be considered as an extension from the diaphragmpart.

The most satisfactory sound reproduction results of this compoundvibrator have been found .When the cone 5 is aflixed to a portion of thediaphragm 2 which is free'to vibrate. Thus, it will be understood thatthe cone 5 shouldinot be attachedito the parts which" bind and support.the diaphragm 2, but should be mounted on some part of the diaphragmthat is free-to vibrate. In the annulartype of diaphragm 2, the cone 5will produce superior results when mounted on some portion of thevibrating diameter of the diaphragm or area. It is desirable in order toobtain some of the most satisfactory reproduction results, to have thatarea of the diaphragm 2 whichis confined within the cone 5, less thanthree-quarters of the total vibrating area of the diaphragm 2. It hasbeen found that the most satisfactoryreproduction is obtained when thecone 5 includes substantially twothirds of the total area .of thevibrating part of the diaphragm.

It is well known that vibrating members such as thediaphragm 2,. whenmounted as herein illustrated, are exceptionally good reproducers ofnotes of high frequencies.

It is also known that the cone loud speakers are exceptionally goodreproducers of notes there is indicated a horn 7 which preferably issupported on cover 4 and which acts as a guard for the cone vibratingelement 5.-

This horn 7 also provides a means for emphfying the sound waves set .invibration y both the diahragm 2 and the cone 5. It will be underjtoodthat the vibration of the diaphragm-2-sets the air around it intovibration, and some of this air is pocketed within the confines of thecone 5 while the rest of the vibrating air will be within the confinesof the horn? and will be amplified thereby. This horn7 also assists inthe amplification of the sound waves set into vibration by the cone 5.

type of Any-suitable means maybe employed to satisfactorily set the comound vibrator mto operation. The particu ar form of means which isherein preferred is specifically illustrated in Figs. 4 to 7 inclusive.It is preferred to employ two electro-magnets 8 and 9 in combinationwith a permanent magnet 10. The electro-mag'nets-a're so mounted thattheir pole pieces 11 and 12 are positioned relativelynear to'thediaphragm 2. Suitable electrical terminals 14 and 15 are shown forconnecting the,electro-magnets to a current producing element. It ispreferred to have the pole pieces 11 and'12 of L shape so that they mayextend down through the windings of the electro-magnets 8 and 9 and befastened to the extremities of the permanent magnet 10, which in thisinstance is preferably made up of three laminated plates ofsemi-circular form.

In most instances it is desirable to adjust the amount of air gapbetween the diaphragm 2 and thepole pieces 11 and 12 of the magnets forthe purposes of locatmg the most sensitive position for the unit to workin, and it is usually desirable to have the pole pieces as near to thediaphragm as possible without having the diaphragm touch them whenvibrating-at its greatest amplitude. In many cases it may be desirableto vary theintensity of operation of the loud speakers, and any suitablemeans may be provided for accomplishing this result. One form ofadjustment which has been found satisfactory in the present apparatusconsists in a means for moving the pole pieces 11 and 12 to and from thediaphragm 2. This is accomplished by mounting the permanent magnet 10and the electro-magnets 8 and 9 on a stem 16 which passes throughthebaseholder 1 and is provided with a suitable nut 17 which' may berotated in one direction or the other to vary the position of themagnets in respect to the diaphragmfQ. The construction preferablyincludes one or more springs 1Swhich tend to force the ole pieces towardthe diaphragm 2. .A suita le type of spring is specifically illustratedin Fig. 7 and it will be noted that 6there are. two of these springsplaced in opposition to one another. If desiredfa single spring 18 maybe employed and the center thereof may engage the. bottom of thebase-holder and'its free ends engage thesemi-circle permanent magnet asmay be readily appreciated by reference to Fig. 6. In Figs. 5 and 6, the

cover 4 is shown as constructed to receive T1118 15 so' the base of asuitable horn. illustrated merely to show the adaptability oftheoperating apparatus, for in Figs. 1

- to 3- this cover 4 ha's'been shown cut away to provide for themounting of a relatively large diameter cone vibrator element and toreceive a suitable cone protecting member orahorn 7.

phragm has been described above in eneral terms, it may be stated thatit may e substantially firmly mounted or fixedly mounted by insertingfibre gaskets at theedges of the diaphragm and between the lip 3 and thecover 4. The diaphragm may be semi-floatingly mounted by using rubbergaskets in place of the fibre gaskets. If desired, the diaphragm mayalso be floatin ly mounted by using annular gaskets, .pre erably of ametal, and providing large wave corrugations in these gaskets, thusmaking them of spring formation. I

It will be noted that the invention in'its simplest form is an improvedloud speaker embodying anovel combination of two vibrating elementswhich are most efiicient regpectively for the reproduction of notes ofdi erent frequencies. The combination of these two vibrating elementsisshown to be accomplished in an improved manner to give a mostsatisfactory, complete and advantageous tone reproduction. It "will benoted that one of the vibrating elements is substantially permanentlyfixed and that the illustrated means for setting the compound vibratorin operation, acts directly upon only one of said elements, i. e. thepermalow frequency impulses. It will further be understood that. the twovibrating elements will vibrate in unison or as an integral structureduringnormal operation, the vi brations of the cone element or part ofthe compound sound reproducing member being dependent upon thevibrations imparted to the disk element or .part thereof, the twoelements therefore being in effect, relatively dependent one upon theother in operation. While it has been herein shown that the means forsetting the compound vibrator in operation acts directly upon thediaphragm 2 which is permanently mounted, it will be understood thatsaid means ma operate upon any part'of the compound v1- bratorconstructedwith the cone part thereof firmly affixed to some portion ofthediaphr'agm which is free to vibrate.

From the foregoing. detailedjtlescription of the preferred embodiment ofthe invention. the operation of my improved sound reproducing .devicewill be readily under into operation, so as to-impart-a vibratorymovement thereto for the reproduction of sounds or notes transmittedtherethrough, the disk diaphragm will obviously be caused to vibrate todifferent extents under low as well i as high frequency impulses, itsfixed position relatively to the pole-pieces of the illustratedenergizing means or unit preventing the same from being flexedsufficiently to be drawn into contact with said pole-pieces, yetpermitting the same freely to vlbrate under the impulses receivedthrough said unit. When operated under high frequency impulses impartedthereto through the energizing unit, the disk'diaphragm will vibrateunder the normal conditions of an ordinary disk diaphragm, with a thecone which is secured thereto vibrating as an integral and unimpeding orunresisting part thereof but acting as a born for the vibrating -port1onof said disk diaphragm, thereby amplifying the sounds emittedtherethrougli.;--. When v operated under-low frequency impulses impartedthereto through the energizing unit,

'the disk diaphragm which is of a higher periodicity than the conediaphragm will be caused to vibrate sufficiently to impart vibrationstherethrough to said cone of lower periodicity so that thelatter will bemore violently vibrated and reproduce the sounds transmitted at thelowerfrequencies, the

horn surrounding said cone serving to am-' plify the sound or soundsreproduced thereby. It will be noted that the cone diaphragm is entirelysupported on the disk diaphragm and has no connection with the born orother element at its outer end and it will therefore be apparent thatthe cone and disk diaphragms comprising the compound vibrating elementare dependent one upon the other in operation, since vibrations can beimparted to the cone diaphragm only through the disk diaphragm whilesaid cone oifers'no resistance to the natural vibrations of the diskdiaphragm which is effectively responsive to the higher frequencyimpulses to which the cone diaphragm will not respond. Thus my improvedsound reproducing device with compound vibratoris adapted .toeffectually and clearly reproduce sounds and notes within a much widerrange of frequency impulses than that to which the ordinary disk andcone diaphragms will individually respond, the one element of the.

compound vibrator being adapted to effectual reproduction of sound wherethe other been herein described in detail a particular embodiment of theinventlon for purposes of full disclosures, and some detailed fea- Itures which are specifically claimed for a special advantage, manychanges and modifications may be made in the particular con: structionand arrangement of parts without departing from .the broad scope of theinvention which is outlined in the appended' claims.

I claim 1. In a sound reproducing mechanism, the

combination of a compound vibrator having that portion thereof whichreproduces notes of high frequencies fixedly mounted and combination ofa compound vibrator having a part thereof fixedly mounted and adapte toreproduce notes of high frequencies and to the vibrating part of thefirst art, said second part beingadapted to repro uce notes of lowfrequencies, and means for operating the compound vibrator.

3. In a sound reproducing mechanism, the

combination of a compound vibrator having fixedly mounted the partthereof which reproduces notes of high frequencies and havlng a secondpart attached to the vihaving a second part thereof firmly attachedbrating portion of the first part,'said second part being adapted toreproduce notes of low frequencies, and means for operating saidcompound vibrator.

4. In a sound reproducing-instrument, the combination of a part adaptedto reproduce notes of high frequencies, said part being mounted in afixed support and being constructed of metal, a second vibrating partattached to a vibrating portion of said first part and being constructedof material other than that of said first part, and means for vibratingsaid parts in unison. v

5. In a sound reproducing instrument,t,he combination of a vibratingpart mounted on a fixed support, a second vibrating part mounted on avibrating portion of said first part, said second part being constructedof a material of lighter-weight than the first part and being of greatersize than the first part, and means for setting said parts intovibration to produce sound waves.

6. In a sound reproducing instrument, the combination of a compoundvibrator having a high frequency vibrating part thereof mounted in afixed support and having a low frequency vibrating part thereof afiixedto a vibrating portion of said first named part and being entirelysupported by said first part, and means for operating said compoundvibrator for reproducing sound waves.

7.. In a sound reproducing mechanism, the combination of a vibratingpart for the reproduction of notes of high frequencies, a secondvibrating part for the reproduction of notes of low frequencies, saidparts being joined together so that only a portion of the vibrations ofone of the parts will be transmitted to the other vibrating part, andmeans acting on one of the parts to vibrate both parts.

8. In a sound reproducing instrument, the. combination of a diaphragmadapted to reproduce notes of high frequencies, a cone shaped vibratingmember mounted on a vibrating portion of said diaphragm, and

means for setting said diaphragm and said cone member into vibration.

9. In a sound reproducing instrument, the.

combination of a diaphragm vibrating memher, a cone vibrating member,saidmemhers being connected together and adapted to reproduce soundWaves, and means mechanically unconnected with either of said membersfor vibrating the same in unison.

10. Ina sound reproducing instrument, a vibrating sound reproducingelement consisting of a relatively flat part mounted in a fixed supportand an extension therefrom in the form of a cone brought intosound'reproducing vibration by the vibrations of said relatively flatpart.

11. In a. sound reproducing instrument, the combination of a diaphragmadapted to be vibrated, a second and cone-shaped diaphragm having itssmall end aflixed uponca limited area of the first diaphragm so that alimited portion of the air set into vibration by the first diaphragmWill be confined Within the cone diaphragm, and means forattached tosaid diap ragm, the diameter of said cone member at the point of attachment to said diaphragm being substantially equal to'two-thirds thediameter of thev1- brating portion of said diaphragm.

14. In a sound reproducing. instrument, the combination of a metaldiaphragm-having its edge clamped .to' 'permanently mount the same insaid' instrument, a cone-shaped 'pape'r vibrating member pasted to avibrating portion of said 'diaphragm,the part of said conemember inengagement with said diaphragm adapted to enclose about twothirds of thevibrating area of said diaphragm.

15. In a sound reproducing instrument, the combination of a diskdiaphragm adapted to be vibrated, a cone vibrating member afiixed to avibrating portion of said disk diaphragm, a horn adapted to surround andprotect said cone and also'aeting to'amplify some of the Vibrations fromsaid disk diaphragm, and means for vibrating said diaphragm and saidcone in unison.

16. In a sound reproducing instrument,

the combination of a disk diaphragm adapted to be vibrated, a conevibrating member supported on a vibrating portion of said diskdiaphragm, a horn adapted to surround and protect said cone and alsoacting to amplify some of the vibrations from said disk diaphragm, meansfor vibrating said disk diaphragm and said cone in unison, and means foradjusting the vibrating means to vary the amplitude of vibration of saiddiaphragm and said cone member.

17. In a sound reproducin instrument,

the combination ofa disk diap ragm adapted to be vibrated, a second andcone-shaped diaphragm aflixed upon a limited area of the diskdiaphragm-so that only a portion of the air set into vibration by saiddisk diaphragm will be confined within the cone diaphragm, means forvibrating said diaphragms in unison, and a horn surrounding saidcone-shaped diaphragm and adapted to amplify some of the vibrations ofsaid disk diaphragm.

18. In a loud speaker, the combination of a base-holder, an annularmetal diaphragm having its edge permanently held in said base-holder, acone-shaped member of aper material having a turned-in flange atits'smallest diameter and adapted to have saidflange" pasted to saiddiaphragm, the

smallest diameterv of said cone being substantially two-thirds of thevibrating diameter of said diaphragm, a horn mounted on said-base-holder and extending therefrom to protect said cone-and actingalso to amplify some of the vibrations of said diaphragm, a magnetfonvibrating said diaphragmand sald cone member, and adjustmg meansresponsive to spring pressures for moving said magnetrelatively to saiddiaphragm to thereby va of vibration of said -diap ragm and said cone.

19. In .a sound reproducing mechanism, the combination of a compoundvibrator having a part thereof adapted to reproduce notes of highfrequencies and havin a second part thereof supported on a vi ratingportion of the first named vibrating part,-

the amplitude I said second named part being adapted to reproduce notesof low frequencies, and means for operating the compound vibrator.

20. In a sound reproducer, a compounddiaphragm being supported on thefirst mentioned diaphragm and so related thereto as to provide an.amplifyin means therefor, together with means or setting the compoundvibrator into operation.

21. In a. sound reproducer, a diaphragm having a high natural period, adiaphragm having a low natural period, said last mentioned diaphragmbeing supported-on the first mentioned diaphragm and vibrated therewith,and means acting directly on one of said diaphragms for setting the samein operation.

22. In a sound reproducer, a compound vibrator, element comprising adisk dia phragm having a high natural period and a cone-shaped diaphragmhaving a low natural period supported thereon and providing anamplifying means forthe former, together with means for setting thecompound vibrator in operation.

23. In a sound reproducer, a diaphragm having a high natural period, adiaphragm having a low natural lperiod and entirely supported on" saidfirst mentioned diaphragm, and means for operatively vibrating saiddiaphragms.

In testimony whereof I afiix my signature.

ARTHUR WILLIAM HARRIS.

